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archive_command vs recovery_command paths
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* archive_command vs recovery_command paths
@ 2014-02-13 00:20 Craig Ringer <[email protected]>
  2014-04-19 19:00 ` Re: archive_command vs recovery_command paths Bruce Momjian <[email protected]>
  0 siblings, 1 reply; 2+ messages in thread

From: Craig Ringer @ 2014-02-13 00:20 UTC (permalink / raw)
  To: pgsql-docs

Hi folks

Another point of confusion I've been seeing a lot in users on Stack
Overflow, dba.stackexchange.com, etc surrounds the meaning of paths
given in archive_command and restore_command.

Lots of people seem to assume that they are both relative to the master,
and that the master will run the restore_command to fetch archives to
send to the replica on request.

(Yes, I know that's completely missing the point of archive-based
replication, but it seems common).

So I think docs changes are needed to the explanations of those options,
and to the replication/recovery section, that better explain that we
assume there's shared storage like NFS involved, and if there isn't you
need to use commands like scp/rsync instead, or use tools like WAL-E.

I'm not going to get time to do this one for at least a few days, but
I'm posting it now partly so I don't forget about it.

-- 
 Craig Ringer                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services


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^ permalink  raw  reply  [nested|flat] 2+ messages in thread

* Re: archive_command vs recovery_command paths
  2014-02-13 00:20 archive_command vs recovery_command paths Craig Ringer <[email protected]>
@ 2014-04-19 19:00 ` Bruce Momjian <[email protected]>
  0 siblings, 0 replies; 2+ messages in thread

From: Bruce Momjian @ 2014-04-19 19:00 UTC (permalink / raw)
  To: Craig Ringer <[email protected]>; +Cc: pgsql-docs

On Thu, Feb 13, 2014 at 08:20:02AM +0800, Craig Ringer wrote:
> Hi folks
> 
> Another point of confusion I've been seeing a lot in users on Stack
> Overflow, dba.stackexchange.com, etc surrounds the meaning of paths
> given in archive_command and restore_command.
> 
> Lots of people seem to assume that they are both relative to the master,
> and that the master will run the restore_command to fetch archives to
> send to the replica on request.
> 
> (Yes, I know that's completely missing the point of archive-based
> replication, but it seems common).
> 
> So I think docs changes are needed to the explanations of those options,
> and to the replication/recovery section, that better explain that we
> assume there's shared storage like NFS involved, and if there isn't you
> need to use commands like scp/rsync instead, or use tools like WAL-E.
> 
> I'm not going to get time to do this one for at least a few days, but
> I'm posting it now partly so I don't forget about it.

I have applied the attached patch which at least clarifies this issue.

-- 
  Bruce Momjian  <[email protected]>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + Everyone has their own god. +


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Attachments:

  [text/x-diff] local.diff (1.7K, 2-local.diff)
  download | inline diff:
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
new file mode 100644
index 17ef25b..4a33f87
*** a/doc/src/sgml/config.sgml
--- b/doc/src/sgml/config.sgml
*************** include 'filename'
*** 2279,2285 ****
        </indexterm>
        <listitem>
         <para>
!         The shell command to execute to archive a completed WAL file
          segment.  Any <literal>%p</> in the string is
          replaced by the path name of the file to archive, and any
          <literal>%f</> is replaced by only the file name.
--- 2279,2285 ----
        </indexterm>
        <listitem>
         <para>
!         The local shell command to execute to archive a completed WAL file
          segment.  Any <literal>%p</> in the string is
          replaced by the path name of the file to archive, and any
          <literal>%f</> is replaced by only the file name.
diff --git a/doc/src/sgml/recovery-config.sgml b/doc/src/sgml/recovery-config.sgml
new file mode 100644
index 9335aca..c9ed2df
*** a/doc/src/sgml/recovery-config.sgml
--- b/doc/src/sgml/recovery-config.sgml
***************
*** 42,48 ****
        </indexterm>
        <listitem>
         <para>
!         The shell command to execute to retrieve an archived segment of
          the WAL file series. This parameter is required for archive recovery,
          but optional for streaming replication.
          Any <literal>%f</> in the string is
--- 42,48 ----
        </indexterm>
        <listitem>
         <para>
!         The local shell command to execute to retrieve an archived segment of
          the WAL file series. This parameter is required for archive recovery,
          but optional for streaming replication.
          Any <literal>%f</> in the string is


^ permalink  raw  reply  [nested|flat] 2+ messages in thread


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